Process of treating fur for felting



Patented July 27, 1943 I 4 l I PROCESS OF TREATING FUR FOR FELTENG Constantine F. Fabian, Brooklield, Coma, assignor, by mesne assignments, to The Frank H. Lee Company, Danbury, Oonn., a corporation of Connecticut No Drawing. Application April 23, 1942,

Serial No. 440,251

1 Claim. This invention relates to a. process whereby fur fibres are modified in order to make them better adapted to use in the manufacture of felt, and particularly the manufacture of felt hats.

The process is applied to fur which has already been carroted, and is particularly valuable when applied to carroted dyed piece fur. that is, fur which has been dyed and which results from the manufacture of fur coats and the like.

The fur of rabbits, hares, beavers, muskrats,

and all the so-called fine furs, possesses inadequate shrinking properties and cannot be used in the raw state form felt. In order to impart felting properties to these furs they are generally treated by brushing the fur while still on the skins have become known in the art as carroting solutions, the process of treatment being similarly called a carroting process. 7

Until quite recently substantially the only carroting solution in commercial use was a solution with certain aqueous solutions, which solutions of mercury nitrate and nitric acid. Due to the v fact that this solution is poisonous, and causes serious mercurial poisoning, attempts have been made for a period of two or three decades to provide solutions which did not contain mercury, and which would at the same time-effect the carroting of fur as well as did the mercury carrot.

Recently new carroting solutions were introduced, which solutions employed certain inhibitors to protect the fur fibres against excessive action of the chemicals in the carroting solution, during both drying and storage of the fur, and also contained anti-oxidants which protected the fibre against excessive oxidation. Such solutions are disclosed and described in Fabian et al. Patents Nos. 2,048,645, 2,087,854, 2,087,855,23087556, 2,087,857 and 2,144,487. The non-mercurial carrots disclosed in these patents have proven to be entirely workable and commercially valuable, and are now universally accepted, so that the old mercurial carrot has now become obsolete in the fur cutting and felt hat industry.

Practically all non-mercurial carrots utilize strong acids such as nitric, sulphuric, phosphoric or hydrochloric acid, and likewise employ strong oxidizers such as hydrogen peroxide, persulphates, perborates, chlorates, etc. in the proper coordination and strength.

Although a large number of theories have been advanced in an attempt to explain the phenomenon of carroting, none has been fully accepted.

they attack the protein of-the animal fibre and degrade the keratin into peptcnes and soluble amino acids.

It has also been found that carroted fur, after being dried and cut from the skin, is strongly acid, its pH ranging from 2.0 to 2.8. These two factors, that is, the presence of water soluble peptones and amino acids, and the presence of excess of free acids, cause dermatitis, particularly on the hands of the laborers who perform subsequent operations during the processing of the fur into felt. Furthermore the two factors mentioned lessen the speed of felting'and detrimentally afiect the quality of the merchandise.

Furthermore, in the case of carroted piece fur, additional factors increase the prevalency of dermatitis and affect the speed of felting and quality of the merchandise even more detrimentally.

- Dyed piece fur, as stated above, is fur made from dressers pieces and old fur coats, and the like. These smallpieces which accumulate in the garment industry are pasted on paper, then carroted, and the fur cut from the skin. It is the general practice in the garment industry to dye fur (usually brown or black) and customarily with para-phenylene-diamine dyes, known to the trade as Ursol, which dyes are active skin irriftants and cause dermatitis. Furthermore the One thing however is undisputed, and that is that dyes are usually fixedby using metal salts as mordants.

' .As a result of the carroting operation, the mordants are converted into soluble metal salts, for example in the case of a chromium salt mordant into toxic bichromate, and the para- .phenylene-diamine dyes become loose and are readily washed from the fur.

By my processing, as hereinafter described, the excess of free acid, the peptones and amino acids of carroted fur, as well as the dyes and mordants of piece fur, are removed from the fur prior to its use in the felting process.

It is an object of the present invention to provide a method of eliminating from carroted fur, whether new fur or piece fur, prior to the formation of felt, the soluble peptones, amino acids and free mineral acid present therein, and to produce fast shrinking fur resulting in tight felt and resulting in little loss of weight of the fur during the felting process.

It is another object ofthe invention to avoid dermatitis among the workers in thefur felting industry, and particularly the felt hat industry.

It is stillan'other object of the invention to render carroted dyed piece fur harmless to the workers, and to thereby enable the hat industry to use such piece fur in the manufacture of felt hats. This is of course particularly important at a time such as the present when the supply of new fur is materially reduced.

It is a still further object of the invention to perform the processing'oper'ation in a relatively short period of time.

The above and other objects of the invention will be best understood from the following description.

Carroted furs, whether new or piece fur, may be greatly increased in commercial and manufacturing value, and also rendered harmless to the workers handling them, if the soluble peptones, amino acids, and excess free mineral acids be removed from the fur. I have discovered that such removal can be effected by the use of hot water at a temperature between 165 and 180 F. Temperatures lower than 165 are not effective and temperatures greater than 180 cannot be used due to the fact that the fur starts to felt.

The removal of peptones, amino acids and free mineral acids may be easily performed by utilizing the well known circulating dyeing machine for loose fur, which'machine is frequently used in the hat making industry and comprises primarily two connected chambers with a circulating pump connected therewith, together with proper inlet and drain valves. The carroted fur is placed in such a machine and the valves so adjusted that fresh hot water at the temperature mentioned hereinabove is continuously forced through the fur by means of operation of the pump. The process is continued until the pI-I value is between 5.5and 6.0.

The fact that the pH value is within the range mentioned indicates that the fur is practically free from mineral acids. peptones, and amino acids, the usual test for this being precipitation by addition of ph'ospho-tungstlc acid to the solution. That is to say, phospho-tungstic acid is added to the solution drained from the fur and when this addition does not cause precipitation the inevitable conclusion is that the fur which has been treated is substantially free from soluble peptones, andamino acids.

After the carroted fur has been subjected to treatment until its value is within the range indicated above, the fur is then dehydrated in a centrifuge and dried in a dryer. When piece fur is treated the color of the treating solution is an indication of the presence or absence of dyeif the solution is clear the fur may be assumed to be free of dye.

While treatment in the manner indicated above is possible it is not commercially practical, since it takes a considerable time and even then thepH value is not within the proper range. For

example in one experiment a quantity of 150 lbs. of carroted fur was placed in the machine and treatment was continuously performed during a seven hour period, at the end of which the pH value was only 3.5.

Corporation. "Igepal C. T. A." is a condensation product of polymerized ethylene oxide.

In use the fur is first immersed in the wetting agent in aqueous solution, and the solution is circulated through the fur for a short period of time. Thereafter the fur remains in the machine, the wetting agent solution being drawn off, and clear water at the proper temperature being circulated for a period of time considertwo and five-eighths ounces.

I have discovered that if wetting agents are added to the fur, in the amount of approximately 1% of the weight. of the fur, then the extraction is effective to bring the pH value within the desired range, in a very short time. The wetting agent may be any of a number the only requirements being that it have a pH value not exceeding 7.3 and that it be stable to acids. I prefer to use a wetting agent known as Igepal C. T. A. manufactured by the General Dyestuff ably longer than that during which the wetting agent is employed.

After this procedure a test by the phosphotungstic acid reaction shows a complete absence of free mineral acids, peptones and amino acids. As an illustration of the use of the method the following is set forth in numbered steps:

1. In one chamber of the dyeing machine, 200 gallons of water was placed, and one and onehalf pounds of Igepal C. T. A."- was dissolved in this water.

2. pounds of carroted fur were placed in the adjoining chamber.

3. When the temperature of the solution in the first chamber reached about to F. the pump was started and the solution was circulated through the fur for fifteen minutes, there being no addition of fresh water.

4. After the fifteen minute period of the third step, the drain valve was opened and the wetting agent solution drawn off. Hot water was then admitted to the intake side of the pump, the drain valve being left open, fresh hot water being thus continuously circulated through the fur for a period of one hour. The water in this step was at the same 170 temperature as was the wetting solution.

As has been stated above, carroted fur, whether from new fur or dyed piece fur, is greatly im-' proved with respect to its felting properties by the treatment mentioned above, and furthermore the loss of weight of the fur during the hat making process is reduced. As an example of this a five pound bag of carroted brown piece fur was divided, one half being used to make hats directly without employing my treatment, and the other half being subjected to my process, and thereafter used in the manufacture of hats. In each instance the amount of fur weighed out for each hat was three and one-quarter ounces.

When the fur was used directly each hat after having been formed on a 27 x 29 inch cone, sized, blocked, and pounced, was found to weigh In other words, during the formation of the hats an average of flve-eighths of an ounce of fur was lost, or 19.2% by weight of theoriginal fur.

When treated with my process there was a loss of approximately 5% of the fur during the treatment. Following the treatment three and onequarter ounces were weighed out for each hat to be formed and it was found that the average weight of the hats (again formed on the 27 x 29 inch cone, sized, blocked and pounced) was three ounces. Thus there was lost during the extraction treatment and the formation of hats 12.3% of the original weight of the fur, which it will be seen is 6.9% less than is lost when my new method was not utilized.

Furthermore, the shrinking time during both the wetting down operations and operations on the Genest B machine was considerably less for the fur which had been processed than for that which had not. For example, in one instance the speed of shrinkage was five rounds on wetting down and twenty-four minutes on the B machine halr rounds on wetting down and fifteen minutes 'on the B machine for the processed fur.

While I have described my processing method for removing i'ree acids, peptones and amino acids, loose para-phenylene-diamine dyes, and other impurities such as mordants from furs. including carroted piece furs, it will be understood that it is applicable to all types of furs, and further that the results are more pronounced in connection with the lower grades, such for example as American and Canadian white tails, and Idaho and Colorado black tails. Therefore I wish it to be understood that I do not wish to be limited by the foregoing description, but rather that y protection be limited only by the appended claim. y

What is claimed is: r The method oi processing carroted fur to render it fast shrinking, capable 0'! providing better felt, and harmless to those performing feltin operations thereupon, which comprises passing through said fur for alperiod of from fifteen to thirty minutes an aqueous solution of a wetting agent stable to acids and having a pH value not exceeding 7.3, said solution being maintained at a temperature of from 165 F. to 180 F., and thereafter draining oil said solution and circulating water at a temperature of from 165 to 180 F. through-the fur until the pH value of the resulting solution lies in the range of from 5.5 to 6.0.

CONSTAN'IINE F. FABIAN. 

